import 'dart:async';
import 'package:flutter/material.dart';
import '../../../core/network/signalr_service.dart';
import '../../../core/theme/app_theme.dart';
import '../../../core/widgets/glass_container.dart';
import '../models/admin_user_model.dart';

/// Modern KPI Header Card Row for Admin Panel Dashboard Overview.
/// Displays real-time live metrics for Users, Administrators, Microservices Health, and MQTT Bus.
/// Continuously updates live EXCLUSIVELY over SignalR WebSockets (`/hubs/health`).
class AdminKpiHeader extends StatefulWidget {
  final List<AdminUserModel> users;
  final SignalRService? signalRService;

  const AdminKpiHeader({
    super.key,
    required this.users,
    this.signalRService,
  });

  @override
  State<AdminKpiHeader> createState() => _AdminKpiHeaderState();
}

class _AdminKpiHeaderState extends State<AdminKpiHeader> {
  int? _totalServices;
  int? _onlineServices;
  bool _mqttConnected = false;
  StreamSubscription<List<Map<String, dynamic>>>? _healthSub;

  @override
  void initState() {
    super.initState();

    if (widget.signalRService != null) {
      _healthSub = widget.signalRService!.healthStream.listen((data) {
        if (mounted && data.isNotEmpty) {
          final int total = data.length;
          final int online = data.where((item) => item['status']?.toString().toLowerCase() == 'online').length;
          setState(() {
            _totalServices = total;
            _onlineServices = online;
            _mqttConnected = online > 0;
          });
        }
      });
    }
  }

  @override
  void dispose() {
    _healthSub?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final totalUsers = widget.users.length;
    final activeUsers = widget.users.where((u) => u.isActive).length;
    final adminCount = widget.users.where((u) => u.role.toLowerCase() == 'admin').length;
    final isMobile = MediaQuery.of(context).size.width < 700;

    final String servicesValue = _totalServices != null ? '$_onlineServices / $_totalServices' : 'SignalR...';

    final String servicesSubtitle = (_onlineServices == _totalServices && _totalServices != null && _totalServices! > 0
        ? 'Alle Dienste online (WebSocket)'
        : (_onlineServices != null ? '$_onlineServices von $_totalServices erreichbar' : 'Verbinde WebSocket...'));

    final Color servicesColor = (_onlineServices == _totalServices && _totalServices != null && _totalServices! > 0)
        ? AppTheme.primaryEmerald
        : (_onlineServices != null && _onlineServices! > 0 ? AppTheme.accentCyan : AppTheme.accentRed);

    final cards = [
      _KpiCard(
        title: 'Benutzer Gesamt',
        value: totalUsers.toString(),
        subtitle: '$activeUsers aktiv • ${totalUsers - activeUsers} gesperrt',
        icon: Icons.people_alt_rounded,
        accentColor: AppTheme.primaryEmerald,
      ),
      _KpiCard(
        title: 'Administratoren',
        value: adminCount.toString(),
        subtitle: 'Vollzugriff auf System',
        icon: Icons.admin_panel_settings_rounded,
        accentColor: const Color(0xFFA855F7), // Purple accent
      ),
      _KpiCard(
        title: 'Mikrodienste',
        value: servicesValue,
        subtitle: servicesSubtitle,
        icon: Icons.dns_rounded,
        accentColor: servicesColor,
        showPulse: _onlineServices != null && _onlineServices! > 0,
      ),
      _KpiCard(
        title: 'MQTT Live-Bus',
        value: _mqttConnected ? 'Aktiv' : 'Offline',
        subtitle: _mqttConnected ? 'SignalR & RPC Bereit' : 'Warte auf WebSocket',
        icon: Icons.sensors_rounded,
        accentColor: _mqttConnected ? const Color(0xFF10B981) : AppTheme.accentRed,
      ),
    ];

    if (isMobile) {
      return GridView.count(
        crossAxisCount: 2,
        shrinkWrap: true,
        physics: const NeverScrollableScrollPhysics(),
        crossAxisSpacing: 10,
        mainAxisSpacing: 10,
        childAspectRatio: 1.5,
        children: cards,
      );
    }

    return Row(
      children: cards
          .map((card) => Expanded(
                child: Padding(
                  padding: const EdgeInsets.symmetric(horizontal: 4),
                  child: card,
                ),
              ))
          .toList(),
    );
  }
}

class _KpiCard extends StatelessWidget {
  final String title;
  final String value;
  final String subtitle;
  final IconData icon;
  final Color accentColor;
  final bool showPulse;

  const _KpiCard({
    required this.title,
    required this.value,
    required this.subtitle,
    required this.icon,
    required this.accentColor,
    this.showPulse = false,
  });

  @override
  Widget build(BuildContext context) {
    return GlassContainer(
      padding: const EdgeInsets.all(14),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text(
                title,
                style: TextStyle(
                  fontSize: 12,
                  fontWeight: FontWeight.w600,
                  color: AppTheme.textMuted,
                ),
              ),
              Container(
                padding: const EdgeInsets.all(6),
                decoration: BoxDecoration(
                  color: accentColor.withValues(alpha: 0.15),
                  shape: BoxShape.circle,
                  border: Border.all(color: accentColor.withValues(alpha: 0.3)),
                ),
                child: Icon(icon, size: 16, color: accentColor),
              ),
            ],
          ),
          const SizedBox(height: 6),
          Row(
            crossAxisAlignment: CrossAxisAlignment.baseline,
            textBaseline: TextBaseline.alphabetic,
            children: [
              Text(
                value,
                style: TextStyle(
                  fontSize: 22,
                  fontWeight: FontWeight.bold,
                  color: AppTheme.textPrimary,
                  letterSpacing: -0.5,
                ),
              ),
              if (showPulse) ...[
                const SizedBox(width: 8),
                Container(
                  width: 8,
                  height: 8,
                  decoration: BoxDecoration(
                    color: AppTheme.primaryEmerald,
                    shape: BoxShape.circle,
                    boxShadow: [
                      BoxShadow(
                        color: AppTheme.primaryEmerald.withValues(alpha: 0.6),
                        blurRadius: 6,
                        spreadRadius: 2,
                      ),
                    ],
                  ),
                ),
              ],
            ],
          ),
          const SizedBox(height: 4),
          Text(
            subtitle,
            style: TextStyle(
              fontSize: 11,
              color: AppTheme.textSecondary,
            ),
            overflow: TextOverflow.ellipsis,
          ),
        ],
      ),
    );
  }
}